Add FLOPs title to table (#3453)

Author: glenn-jocher

README.md

@@ -30,7 +30,7 @@ This repository represents Ultralytics open-source research into future object d
 
 [assets]: https://github.com/ultralytics/yolov5/releases
 
-Model |size<br><sup>(pixels) |mAP<sup>val<br>0.5:0.95 |mAP<sup>test<br>0.5:0.95 |mAP<sup>val<br>0.5 |Speed<br><sup>V100 (ms) | |params<br><sup>(M) |<br><sup>640 (B)
+Model |size<br><sup>(pixels) |mAP<sup>val<br>0.5:0.95 |mAP<sup>test<br>0.5:0.95 |mAP<sup>val<br>0.5 |Speed<br><sup>V100 (ms) | |params<br><sup>(M) |FLOPs<br><sup>640 (B)
 ---   |---  |---        |---         |---             |---                |---|---              |---
 [YOLOv5s][assets]    |640  |36.7     |36.7     |55.4     |**2.0** | |7.3   |17.0
 [YOLOv5m][assets]    |640  |44.5     |44.5     |63.1     |2.7     | |21.4  |51.3